package net.minecraft.server.jsonrpc.api;

import com.mojang.serialization.Codec;
import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.List;
import java.util.Optional;
import net.minecraft.resources.Identifier;
import org.jspecify.annotations.Nullable;

public record MethodInfo<Params, Result>(String description, Optional<ParamInfo<Params>> params, Optional<ResultInfo<Result>> result) {
	public MethodInfo(final String description, @Nullable final ParamInfo<Params> paramInfo, @Nullable final ResultInfo<Result> resultInfo) {
		this(description, Optional.ofNullable(paramInfo), Optional.ofNullable(resultInfo));
	}

	private static <Params> Optional<ParamInfo<Params>> toOptional(final List<ParamInfo<Params>> list) {
		return list.isEmpty() ? Optional.empty() : Optional.of((ParamInfo)list.getFirst());
	}

	private static <Params> List<ParamInfo<Params>> toList(final Optional<ParamInfo<Params>> opt) {
		return opt.isPresent() ? List.of((ParamInfo)opt.get()) : List.of();
	}

	private static <Params> Codec<Optional<ParamInfo<Params>>> paramsTypedCodec() {
		return ParamInfo.typedCodec().codec().listOf().xmap(MethodInfo::toOptional, MethodInfo::toList);
	}

	private static <Params, Result> MapCodec<MethodInfo<Params, Result>> typedCodec() {
		return RecordCodecBuilder.mapCodec(
			i -> i.group(
					Codec.STRING.fieldOf("description").forGetter(MethodInfo::description),
					paramsTypedCodec().fieldOf("params").forGetter(MethodInfo::params),
					ResultInfo.typedCodec().optionalFieldOf("result").forGetter(MethodInfo::result)
				)
				.apply(i, MethodInfo::new)
		);
	}

	public MethodInfo.Named<Params, Result> named(final Identifier name) {
		return new MethodInfo.Named<>(name, this);
	}

	public record Named<Params, Result>(Identifier name, MethodInfo<Params, Result> contents) {
		public static final Codec<MethodInfo.Named<?, ?>> CODEC = typedCodec();

		public static <Params, Result> Codec<MethodInfo.Named<Params, Result>> typedCodec() {
			return RecordCodecBuilder.create(
				i -> i.group(Identifier.CODEC.fieldOf("name").forGetter(MethodInfo.Named::name), MethodInfo.typedCodec().forGetter(MethodInfo.Named::contents))
					.apply(i, MethodInfo.Named::new)
			);
		}
	}
}